80 Original Articles. [ Jan. 
partly in the organism itself, and partly in the external agencies to 
which it is subjected. That condition which is inherent in the 
organism, being derived hereditarily from its progenitors, may be 
conveniently termed its germinal capacity : its parallel in the Inorganic 
world being that fundamental difference in properties which consti- 
tutes the distinction between one substance, whether elementary or 
compound, and another; in virtue of which each “behaves” in its 
own characteristic manner when subjected to new conditions. 
Thus, although there may be nothing in the aspect or sensible 
properties of the germ of a Polype to distinguish it from that of a 
Man, we find that each developes itself, if the requisite conditions be 
supplied, into its typical form, and no other ; if the developmental 
conditions required by either be not supplied, we do not find a different 
type evolved, but no evolution at all takes place.* 
Now the difference between a being of high and a being of low 
organization essentially consists in this ;—that in the latter the con- 
stituent parts of the fabric evolved by the process of growth from the 
original germ are similar to each other in structure and endowments ; 
whilst in the former: they are progressively differentiated with the 
advance of development, so that the fabric comes at last to consist of 
a number of organs or instruments more or less dissimilar in structure, 
composition, and endowments. 
Thus in the lowest forms of Vege- 
able life, the primordial germ 
multiplies itself by duplicative 
subdivision (a, b, c, d) into an 
apparently unlimited number of 
cells, each of them similar to every 
other, and capable of maintaining 
its existence independently of © 
them. And in that lowest Rhi- 
zopod type of Animal life, the 
knowledge of which is among 
the most remarkable fruits of 
modern biological research, “ the 
Physiologist has a case in which 
those vital operations which he 
is elsewhere accustomed to see carried on by an elaborate apparatus, 
are performed without any special instruments whatever; a little 
particle of apparently homogeneous jelly changing itself into a greater 
variety of forms than the fabled Proteus, laying hold of its food with- 
* Tt is quite true that among certain of the lower tribes both of Plants and 
Animals—especially the Fungi and Hntozoa—similar germs may develope them- 
selves into very dissimilar forms, according to the conditions under which they 
are evolved; but such diversities are only of the same kind as those which 
manifest themselves among dndividuals in the higher Plants and Animals, and 
only show that in the types in question there is a less close conformity to one 
pattern. Neither in these groups, nor in that group of Foraminifera in which 
I have been led to regard the range of variation as peculiarly great, does any 
tendency ever show itself to the assumption of the characters of any group 
fundamentally dissimilar. 
